Most
gray matter volumetric studies use T1-weighted imaging such as MP-RAGE
because it provides good contrast between white matter and cortex. However,
due to susceptibility artifact coming from the air-tissue interface, a
reliable and accurate measurement is difficult in the regions near the
air-bone interface for T1-wieghted schemes. One way to alleviate this problem
is to perform gray matter spin-echo imaging through DIR sequence. One
drawback of the DIR sequence, however, is its long scan time. We applied one
of the parallel imaging reconstruction schemes, GRAPPA scheme, to DIR imaging
to evaluate measurement changes as a function of reduction factor.